Sound producer



May 25, 1937.

J. F. EBERT SOUND PRODUCER Filed June 1'7. 1935 Patented May 25, I937 UNITED STATES SOUND PRODUCER Joseph F. Ebert, Hollis, N. Y., assignor to Signal Engineering 82 Manufacturing Company, New York, N. Y., a corporation of Massachusetts Application June 17, 1935, "S eria1 No'.27,004

2 Claims.

The present invention relates to electromagnetic sound producers commonly known as horns, of the type in which an elastic diaphragm is vibrated through pulsations set up by a varying magnetic field.

In Patent No. 1,312,373 issued August 5, 1919 to Wheelock there is shown and described a sound producer of the above indicated character, and the object of the present invention is to provide an improved horn construction in which the parts may be quickly and readily assembled so as to reduce to a minimum the cost of manufacture. In the improved construction, the utilization of bolts and nuts for securing the parts together is dispensed with, thereby overcoming the tendency for such small parts to become loosened as a result of vibrations set up by operation of the horn. The above and other advantageous features of the invention will hereinafter more fully appear from the following description taken in connection with the accompanying drawing, in which:

Fig. 1 is a view in side elevation of a horn embodying the invention.

Fig. 2 is a transverse sectional view of the parts of Fig. 1.

Fig. 3 is a vertical sectional view along the line 22 of Fig. 1.

Fig. 4 is a view similar to Fig. 1, partially in section, illustrating a modification of the inven tion.

Like reference characters refer to like parts in the diiierent drawings.

Referring to the drawing, the horn comprises a cylindrical casing I formed from steel tubing such as is readily obtainable in stock sizes, with each end of the casing providing a groove 2. Each groove 2 consists of a flat portion 2a, of uniform diameter and a concave portion 2b near the open end of the casing, the purpose of which will hereinafter appear.

In the assembled horn, the portion 2a of each groove closely receives an offset disk 3 and a diaphragm 4, with a magnetic plunger 5 having its ends bearing on the spaced diaphragms 4. One of the disks 3 carries a magnetic structure consisting of a pair of coils Ii, 6, mounted on a magnetic core I located centrally of the disk. Each disk 3 provides a central opening 3a for slidably supporting the plunger 1 at its ends, and an armature 8 is carried by the plunger so as to be attracted by the coils 6 when the latter are energized. With the above construction, it is evident that upon energization of the coils 6 by alternating or interrupted current, a reciprocatory movement is imparted to the plunger 5, thereby vibrating the diaphragms 4 in engagement with opposite ends of the plunger to produce sound which passes out both ends of the casing. In order to protect the diaphragms 4 from injury, an open work grill 9 is provided at each end of the casing I, each grill having a ring Ill also fitting the groove portion 2a.

When assembling all the parts of the horn within the casing I, the disk 3 carrying the magnetic structure, together with a diaphragm 4 and a grill 9, are placed in the groove portion 2a at one end of the casing I, and. the parts are locked in position by means of a snap ring II forced into the concave portion 2b of the groove. The plunger 5 carrying the armature 8 is then inserted through the opening 3a of the disk already in position to engage the diaphragm 4, after Which the other. disk 4 is placed in position in the groove at the opposite end of the casing to center the plunger 5. Assembly of the parts is then completed by placing the second diaphragm 4 and grill 9 in position against the second disk 3, and locking these parts with another snap ring II. The completed device is then substantially a unit, in which the parts cannot become displaced as long as the snap rings I I remain in position.

Referring now to Fig. 3, there is shown a modification of the construction in which the grills 9 are replaced by plates I2, each having a flange I 2a for receiving a horn I 3, the plates being locked by snap rings II in the same manner as the grills. If desired, each plate I2 may be provided with an adjusting screw I4 having its end bearing on the associated diaphragm 4 for the purpose of controlling the tension and the tone of the diaphragm.

From the foregoing, it is apparent that by the present invention there is provided an improved construction for a sound producer, such as a horn, whereby all the parts of the same may be quickly and readily assembled so as to provide a substantially unitary structure, without the use of screws and other securing devices such as might become loosened due to the vibration of I the sides toward the casing ends, outwardly convex apertured members each having a rim portion positioned against the rim portion of a diaphragm, means for securing the plate, diaphragm and apertured members in position at each end of the casing, a pin extending between and bearing against both diaphragms, an armature mounted upon the pin, an electromagnet for actuating the armature to reciprocate the pin, and means for mounting said electromagnet upon one of said plates and between the same, said plates providing openings to slidably support and guide said pin in its reciprocatory movement.

2. An electromagnetic sound producer, comprising a cylindrical casing having a shoulder formed near one open end of the casing on the inside, a plate member positioned against said shoulder and being concave inwardly from the end of the casing, a diaphragm positioned on said plate member on the side of the plate toward the open end of the casing, an outwardly convex apertured member having a rim positioned against a rim portion of said diaphragm, means for securing the plate, diaphragm and apertured member in position against said shoulder, a pin member extending through an opening in said plate member and bearing against said diaphragm, an armature mounted upon the pin member, an electromagnet for actuating the armature to reciprocate the pin, and means for mounting said electromagnet upon said plate between the plate and said armature, the opening in said plate serving to guide said pin in its reciprocatory movement by said electromagnet.

JOSEPH F. EBERT. 

